U.S. Pat. No. 5,261,862 has disclosed an arrangement of components for a multi-step automatic transmission in which one shifting element designed as multi-disc brake and one free wheel functionally coordinated with said multi-disc brake and designed as a roller free wheel are disposed side-by-side in an axial direction. The free wheel here abuts axially directly against a disc set of the multi-disc brake. One transmission housing forms the outer disc carrier of the multi-disc brake with a spline section in which non-torsionally and axially movably engages the outer discs of the multi-disc brake and one outer ring of the free wheel. The free-wheel outer ring is fixed in the axial direction, on one side, via a guard ring which engages in a groove of the disc spline section of the transmission housing. When the multi-disc brake is actuated, the discs support themselves in the axial direction against the free-wheel inner ring which, in turn, supports itself via a supporting disc on the guard ring by which the free-wheel outer ring is axially fixed. An inner disc carrier of the multi-disc brake has a spline section in which both the inner or lining discs of the multi-disc brake non-torsionally and axially movably engage the same as an inner ring of the free wheel.
As an assembly sequence in the arrangement of components of U.S. Pat. No. 5,261,862, one hydraulic actuating device (piston, recoil spring) is evidently first introduced in the transmission housing, then the disc set, then the free wheel and then the supporting disc and subsequently the guard ring is assembled for axial fixing. The inner disc carrier of the multi-disc brake is thereafter assembled in a subsequent step.
A similar arrangement of components with one multi-disc brake and a free wheel, functionally coordinated with said multi-disc brake, which abuts axially directly against a disc set of said multi-disc brake is also known from U.S. Pat. No. 6,120,410 for a multi-step automatic transmission with a non-coaxial input and output. Unlike the above described arrangement of components of U.S. Pat. No. 5,261,862, the disc set supports itself when the multi-disc brake is actuated, not via the free wheel on the transmission housing but via a separate first guard ring which engages in a corresponding groove of the disc spline section of the transmission housing. The free-wheel outer ring, which abuts against an outer disc of the disc set remote from the hydraulic actuating device of the multi-disc brake and is designed as an end disc, is non-torsionally introduced in the transmission housing. A second guard ring of said arrangement of components fixes the free-wheel outer ring in the transmission housing axially against the guard ring of the disc set. The inner disc carrier of the multi-disc brake and the free-wheel inner ring are designed in one piece as part of a cylindrical planet carrier of a planetary gear set situated, seen in the radial direction, below the multi-disc brake. Said cylindrical planet carrier, in addition, has upon the side of the disc set opposite the free-wheel one other spline section for accommodating discs of another multi-disc clutch which are, likewise, situated radially above the planetary gear set. The whole free-wheel with clamping bodies, a clamping body sprag unit and a free-wheel outer ring, together with the cylindrical planet carrier, conveniently form one assembly unit.
During the assembly of the multi-step automatic transmission comprising non-coaxial input and output as disclosed in U.S. Pat. No. 6,120,410, the hydraulic actuating device (piston, piston recoil spring) is evidently first introduced in the transmission housing of the multi-disc brake, thereafter a pre-assembled unit of the multi-disc clutch consisting of the outer disc carrier, the actuating device and the disc set. Due to the geometric dimensions of the multi-disc clutch, the disc set of the multi-disc brake can only be introduced just now in the transmission housing. Subsequently, the disc set is axially secured by the assembly of the first guard ring. During the assembly step that follows, the pre-assembled planetary gear set with its planet carrier (and the pre-assembled free-wheel) can be introduced in the transmission, both the disc spline sections of the multi-disc clutch and of the multi-disc brake with the corresponding spline sections of the corresponding lining or inner discs have to be brought to engagement and the positive fit of the free-wheel outer ring has to be produced in the transmission housing. Only thereafter does axial fixing of the free-wheel outer ring take place by the assembly of the second guard ring in the corresponding groove of the housing. It can be clearly seen that said assembly is costly, especially with regard to the “threading” of the cylindrical planet carrier with its two disc spline sections and the pre-assembled free-wheel.
U.S. Pat. No. 6,120,310 discloses one other arrangement of components for another automatic transmission with a coaxial input and output with one multi-disc brake and one free-wheel functionally coordinated therewith whose free wheel outer ring abuts axially directly against a disc set of said multi-disc brake. The transmission housing, in turn, forms the outer disc carrier of said multi-disc brake, the outer discs of the multi-disc brake are correspondingly introduced non-torsionally and axially movably in a disc spline section of the transmission housing. Starting with the assembly sequence, the hydraulic actuating device (piston, piston recoil spring) of the multi-disc brake must be first introduced in the transmission housing. The disc set of the multi-disc brake, after being assembled, is axially by a guard ring fixed in one direction that engages in a groove of the housing. The free wheel is located on the side of the disc set opposite to the hydraulic actuating device. The free-wheel outer ring abutting against the disc set here non-torsionally engages a spline section of the transmission housing without axial fixing. The free-wheel inner ring, as an input element of the free wheel, is firmly connected with a planet carrier which, in turn, is firmly connected with the inner disc carrier of the multi-disc brake. Therefore, in said arrangement of components of U.S. Pat. No. 6,120,410, the complete free wheel consisting of the free-wheel outer ring, the clamping body, the clamping sprag unit and the free-wheel inner ring is always assembled also together with a (pre-assembled) planetary gear set.
Known exclusively from the Applicant's not pre-published German patent application DE 101 31 816.2 is a clutch arrangement with two shifting elements respectively designed as multi-disc brakes and axially disposed side-by-side. One common outer disc carrier, discs of both multi-disc brakes and a hydraulic piston recoil device associated with each individual multi-disc brake form a pre-assemblable unit. The whole outer disc carrier is non-torsionally assembled in a transmission housing. Hydraulically actuatable pistons for operating the multi-disc brakes are each situated on the side of the respective disc set which lies opposite to the free wheel. A functional tying of the multi-disc brakes on a free wheel is not provided.
The problem on which this invention is based is to produce a shifting element system for a transmission comprising at least one shifting element and one free wheel functionally coordinated with the shifting element and whose structural elements can be assembled as easily and safely as possible in the transmission.